How to Install a Cigarette Lighter Plug: Strip and Crimp 12 Volt Wire

Today I want to look at one of the simplest of all projects, but one that all of us should know how to do. The main value of this simple project is it will show you how to strip and crimp wire. Once you know how to do that a whole world of simple 12 volt projects open up to you. I know many of are already groaning to yourself that this is simply beyond your capacity so you are going to stop reading right now—PLEASE DON’T!!! At least give me a chance to change your mind. It is short, mostly pictures and won’t take long so just hear me out! There are lots of 12 volt appliances that come with cigarette lighter plugs so you should have one for your house batteries. If you don’t, this post will show you how.

You need to buy 4 things to make this project work:

A cheap Stripping/Crimping tool from Walmart,

A Roadpro Cigarette Lighter Outlet from a truck stop or from Amazon.com.

Two 3/8 inch, 16/14 gauge Ring Connectors

A house battery to connect it to.

This is the first thing you need, a simple receptacle to plug your cigarette lighter appliances into:

The next thing you need is a stripper-crimper. This is a simple tool you can buy from the automotive section of Walmart for less than $5.

It does three things:

Cuts Wires

Strips the rubber cover off the end so you can get into the bare wire underneath.

Crimps on connectors.

The pictures below will make that start to come clear.

All the 12 volt appliances you buy need to be connected to your battery to draw power. Fortunately many come with cigarette lighter plugs, so that is easy. But many others just come with two raw wires coming out of them, one positive and one negative. It’s up to us to find a way to connect them to the battery. To do that we are going to use connectors that we strip and crimp onto the bare wires coming out of the appliance.

The two connectors we will use most are butt and ring connectors. We will use a butt connector to connect two bare wires-usually to make them long, like an extension cord. Essentially a butt connector is the way we connect two wires together permanently as an extension cord. A Ring connector goes at the end of the wire and is how we connect an appliance to the battery. Most batteries come with posts that have nuts on them. All we have to do is take the nut off, slide the ring connector down over the post, and tighten the nut back on (photos of this below).

Here is a picture of some of the most commonly used connectors, including Ring and Butt Connectors. Our cigarette lighter plug-in came with 6 foot wires, so we don’t need a butt connector to make it longer. We just need ring connectors to attach it to the battery. You will notice that some ring connectors come with small rings and some with big rings. Since ours needs to go over the lug of your house battery (which is pretty big) we need the larger, 3/8 inch rings. You can buy them at Walmart as well. At the bottom of the post are links to packages of them from Amazon.com.

So lets get started. The Roadpro comes with a 6 foot cord and for most of us that should be long enough. 12 volt electrical wire comes with strands of copper wire wrapped inside a rubber sheath. To get to the copper wire we need to strip about 3/8 inch off the end of the rubber sheath:

Next I need to crimp on the ring connector to the bare end of the wire. So I slide the the bare metal into the end of the connector and use the crimping part of the tool to squeeze it down tightly on the connector. That squishes (yes, that is the technical term!!) it down tightly on the wire so electricity flows freely through it. As you look at the pictures, you will notice a gap in the metal of the connector, you want to squeeze down squarely on it because it spreads the easiest.

The ring connectors after I crimped them on. Notice I squeezed down on the gap in the metal of the connector and it spread around the exposed copper wire. After you are done crimping, ALWAYS give the connector a good tug on the wire to see if it is held tightly by the connector.

You have now stripped and crimped a 12 volt outlet for your new house batteries. To finish the job you just use a pair of channel lock pliers to loosen and remove the nut on the battery, slide the ring connector down over the stud and re-tighten the nut.

And that’s it!! You did this whole job in about 30 minutes and it made your life a lot better!

I just kept using these few simple skills to do more and more complex things. One day I realized that I had all the knowledge and skill I needed to install solar panels. All I had to do was strip and crimp wires coming form the solar panel to go into the solar controller. Then I had to strip one end of a wire to go into the solar controller and strip and crimp ring connectors to go onto the the battery (I also stripped and crimped a fuse onto the positive wire, but more about that another day!). My point is, once you have mastered stripping and crimping, the sky is the limit!

The cheap tools you buy at Walmart work okay, but I got tired of them and bought high quality Channel-Lock tools from Amazon, and it made the job so much easier! But they are expensive and you have to buy three tools to do the three jobs. It was well worth it to me:Channellock 908 Wiring-Stripping Tool

I agree with Lee, a fuse holder installed as close to the battery as possible is cheap insurence from electrical fire in case of a short circuit. Just one more part (fuse holder), a butt connector and two more crimps and your golden. No harder to do than anything else here, just a couple extra steps.

Guy, every cigarette lighter device I have ever seen comes with a fuse in the plug, so I thought that would only add complexity to something I wanted to be very simple.

Beyond that, there is a big variation in fuse sizes for cigarette lighter devices. Many are 5 amp, some go up to 15 amp. So a 5 or 10 amp fuse would keep some devices from working, and a 15 amp fuse would provide no protection for many devices.

Hi Bob,
The fuse in the plug is there to protect the device your powering. This is why you’ll see different sizes there depending on the device. But what I was refering to, due to a mishap of my own, was protecting the wiring between the outlet and battery. Luckily I didn’t have a fire, but the wires did get very hot and had to be replaced when the insulation rubbed off on a metal edge and short circuited. A fuse placed near the battery would have prevented all my troubles and is always installed now. I like your take it slow aproach, but safety is important too. Besides, it’s just two more strips and crimps, the fuse holder is an easy devise to add and give us a well protected circuit.

Lee, every cigarette lighter device I have ever seen comes with a fuse in the plug, so I thought that would only add complexity to something I wanted to be very simple.

Beyond that, there is a big variation in fuse sizes for cigarette lighter devices. Many are 5 amp, some go up to 15 amp. So a 5 or 10 amp fuse would keep some devices from working, and a 15 amp fuse would provide no protection for many devices.

I just finished installing a new lighter plug in my van and it had no incorporated fuse. Many do not have a fuse installed in the outlet but will say in tiny print on the package that you should install a fuse inline. I also installed it to a switch and into a box for convenience.

A big gripe of mine is most of these outlets do not list their max amp rating so you don’t know how good the unit is. I also use heavier 12 ga wire and the yellow connectors since bigger always means less resistance and cooler running. Under-sizing DC wires is a big problem and the cause of many fires. These safety features are important and failure to note them is why many people get into trouble with electricity then are scared to death of it. Otherwise, nice clear post/instructions.Mary recently posted…Thinking …

Mary, you are quite right and those all all very good points. However, I think I know my audience and had I tried to cover all the ground you did in this paragraph, I would have totally lost them. We are doing ABC and that’s all.

I’ve never seen a fuse in the female outlet, it is always in the male plug attached to the appliance. It has always been my understanding that the car manufacturers limited cigarette lighter plug to 150 watts, about a little over 10 amps, so every appliance with a cigarette lighter plug was designed for less than 150 watts. with that little power wire size shouldn’t be an issue unless it is a very long run. In this case it was 6 feet so it only needed a small wire and I thought would just confuse newbies.

Right Lee, as we build on what we already covered, we will add new ideas. For someone who has no experience in 12 volt, their eyes glaze over and they are totally lost if you start throwing these things out at them.

I think the only real skill I have is to put myself in the place of my reader and try to see and feel the way they do. Then I try to talk to them like I would like to be talked to. Sometimes it works, sometimes it doesn’t!
Bob

Well, I did read almost all of it; by the time you got to the “other things you can do” section I was pretty confused. So –

The whole point behind this is to connect a 12-volt appliance to the battery via a plug, yes? What do you do if the appliance doesn’t have a plug? I think you said some of them don’t… Also, what do you do if you have regular (120 volt) appliances too? Those would need an inverter I think. Can you connect an inverter to the same battery or do you need a separate battery for that? And when the outlet is connected to the battery you said something about the negative wires being red, except in the picture there is also a yellow wire and one that looks kind of copper; are those also negative? Why are there so many in the same place? Is that how many come with the outlet or is there something else that needs to be attached too?

Just one other thing – the two comments above are talking about fuses; what do those do (I’ve never really understood that) and how would you add them to this kind of setup?

I’m sorry for all the questions but the whole subject of electricity is overwhelming to me (and actually one of the biggest things that scare me about vandwelling).

Meg, the problem is the entire subject is much too overwhelming, that’s why so many people close down to it. In this post I wanted to teach you one thing: how to strip and crimp wire. Forget all your other questions!! Did you learn how to strip and crimp wire? Could you do this one simple thing I tried to teach you?

If you did, then we can build on that and learn more things. If you need to know everything at once, chances are you will never know any of it–or you are about 1000 times smarter than I am.

When you teach a child to read, you start with the ABCs, you don’t include split infinitives or past and present participles (it’s a good thing because I have no idea what either of those are and have no intention to ever learn). When it came to 12 volt power, I was a child when I started and so I started with the ABCs. Unfortunately, that is the only way I know how to teach it.
Bob

It has all to deal with Ohms law and different things that can happen. It basically breaks the connection when too much Electricity current (Amps) is going that point in the wire. He is right though. If I go more into this it will be overwhelming. lets just say if too much flow goes through the wire it will over heat and burn and this will cut the connection because it the fuse will blow. This is also why it is a bad idea to put bigger fuses in when they blow a lot. I have seen this too many times working on Semis

Greg, that is a great idea! I know how hard electrical wiring is for people so I want to start with extreme simplicity and very slowly work up in complexity. For this job, I assumed the person knew nothing. Hopefully I will keep it going as a series and work our way up.

Success does breed success, but, failure breeds failure just as well. I wanted this to be extremely simple so it met with success. This project came with all the wire they needed so they didn’t need to know about wire sizes.
Bob

Replies are good. Fuses would be important to mention. Meg, the fuse goes on the wire that attaches to the Positive terminal… if something goes wrong, it cuts off the current to the device.. preventing overcharging and burning out the device. Then you can fix the problem and replace just the little fuse.

12v items can be directly wired to the 12v battery, with the connectors and don’t have to be plugged into a cig/power outlet plug. My refridg is hard-wired direct to the battery as well as a few other devices… that’s why on the battery terminal there are several different wires with connectors… you can stack them on the post. Bob’s photo above shows four different devices connected to the battery. One could be just the 12v power/cig lighter shown in the first photo. Bob is only talking about 12v power items here. Of course, your 110v items must have an inverter… which would be wired with connectors direct to your battery, like the other four items.

I understand your confusion/fear… I was there once too… but it is pretty simply. I think Bob did an excellent job of illustrating the basics of how to wire things. It could be expanded into a book, but this is a good summary.Charlene Swankie recently posted…Great Resources for Newbies to the Tribe.

I wouldn’t say it always go on the Positive terminal. At times you will find it on the ground. I have seen switches fuses relays ect all off of the ground side. Especially with newer things out there. This actually works because of Electron Theory of electrons actually moving from Neg to Pos.

Yes, I would love to see more posts about diy electrical as it’s all new to me, and I have concerns about safety after viewing a few nasty rv fire photos.

This article was very helpful. Having never actually seen a deep cycle battery, I was initially confused about the “lug and nut” because I don’t see that on a car battery. Now that I’ve looked at a few images, I see that they are a little different.

I also initially thought that “everything” came with a connector on the end until you pointed out otherwise.

Also, thanks to Charlene for the fuse explanation. That was very helpful. So, yes to more, more-easy does-it simple posts on electrical!

McBe, one of the big problems when learning anything new is that they all have their own language. Since it is new, you obviously don’t know the language so all the jargon is very confusing. So when trying to start at the most basic level I try to use alnguage most people can relate to and so I thought everyone would know what a lug and nut was because of wheel lugs. That was probably a mistake.

However, a picture can cut right through all the weirdness of language so it sounds like that worked for you.

In my experience, other than appliances that have a cigarette lighter plug, most come with two, short, wires. The reason is that there are a huge number of variables that affect the size of wire and connector that you will use to install the device. Most manufacturers simply give you the device and let you figure it out from there. of course some items come as kits with everything you need, but those are the exceptions
Bob

I would love to see more on this and related topics. I am especially interested in DIY solar power as my next rig (the one I hope to hit the road in) will have it. I’m sure you’ve touch on the topic of solar power elsewhere, but a review/explanation of the nuts and bolts of DIY installation of solar panels and related components would certainly be welcome.

Walt, I plan this to be an ongoing series working our way up the complexity scale. I’ve written a lot about solar installs. If you look on the right side of the blog there is a list of categories. One of them is solar. Click on it and it will list the posts on solar.
Bob

Good luck on that self-discipline to Keep It Simple, Bob! Very tough to keep it to baby steps when experience tempts you to throw in the kitchen sink.
Personally, I flip the stripper front-to-back from what you have in your photo, so that the unwanted insulation is being pushed off by a flat surface instead of being wedged toward the wire strand. But the way you have it makes for a better photo that’s much easier to understand anyway. I also seldom rotate the stripper around the wire in any way – but that might be because the more expensive strippers leave less of the jacket uncut. As you said, if you’re going to use them more than a few times in the long run, quality wire strippers are one of those things that are well worth the extra money because they do the job with less hassle and effort. If the particular wire doesn’t want to strip on the first pull, only then I’ll turn it a little and try again.

But see? – here I am adding in stuff that would unnecessarily complicate. Get to fuses and stuff later in a separate post. You can’t mention something without defining and explaining it. If you mention fuses (which are not within the focus of this post) then you need to get into defining, explaining and choosing them: ratings, types, etc. That begs getting into wire gages and lengths… Keep writing for all the people who are intimidated and don’t know, not to satisfy those who already do. There will always be omissions, because there need to be. 101 presentations are not supposed to be complete – Just short and sweet!DougB recently posted…Junker or Jewel?

Thanks Doug, you are right, it has to be kept very very simple or you loose people. When I started out I had never stripped and crimped wire before and so I looked for info on the net to explain it and I couldn’t find anything. So I just learned the hard way. I just wanted to give people a very basic into to it.

I am not a quick learner, even simple things can be difficult for me, so I write to those people who are like me and are not quick learners.
Bob

Bob-Thanks for this beginners lesson. We all need to first crawl and then walk. Although I’m a bit beyond Lesson #1, I read every word of your explanation and it reinforced everything I know. Thank you for the refresher.

BTW-I had my 13 year old son read the post as well and even though he has stripped a wire or two, he really liked the layout of the steps and pics. He’s had me in his ear before, maybe he’ll remember your lesson simply b/c it’s new. Thanks for a new take on a lesson.

And just for me, I love to get “into the weeds” of the details. Pictures of your mundane are encyclopedic to novices. I know pics equal bandwidth. Thank you for that.

While you’re picking up the wire strippers/crimpers at Walmart, you can get the 12V outlet there too. The ones I got there look just like the one in the tutorial, but with a different sticker on the cover flap.

On the same Walmart rack as the outlets are inline fuse holders and, if you want, small on-off switches.

Thanks Bob. I am bookmarking your site. I am just learning about 12 volt wiring in preparation for rewiring my vintage trailer. I know I have a lot to learn. Other sites I feel are way over my head. It is the simple basics that ‘experts’ often forget to mention. I like the idea of starting with a simple project and then getting more understanding through getting hands-on.

Thank you, Bob, for undertaking this project of explaining some of the basics of 12 volt wiring. I had been searching in vain online and at the library. I recently bought a vintage 1977 Holiday Rambler in excellent shape. I liked it so much I decided to live in it full time. So I set it up in the woods about 200 feet from the house of a good friend in the Texas Hill Country. I soon found out that charging my phone, digital music players, etc. at the end of a long extension cord eventually wrecks the batteries. So I embarked on a new project of trying to expand the 12 volt charging capability of my Toyota Previa van. The simple wiring issues I faced had intimidated me, but the information you provided has definitely helped to get me moving forward again.

It’s a lot later now, but it’s important, VERY important, to use fuses at the power source. That’s why houses and other buildings have all those circuit breakers in a big box where the main power is. The circuit breakers or fuses are there to prevent a wire from carrying more current that it is rated for. Too much current causes the wire to overheat and that can start a fire. Many, many house fires are caused by electrical problems like overloads. The fuses & breakers are not there to protect appliances or other plug-in devices. They are there to prevent fires. I designed a lot of industrial electrical control panels and had to learn the rules of the National Electrical Code, and then more rules for making the control panels acceptable to Underwriters Labs. These rules were all for fire safety and personnel safety. None were for protecting the device using the power.

I hope this note clarifies the need for fuses. Thanks for a really helpful web site!

Kerry Ann, to the best of my knowledge there is no such thing. You could possibly run a 110 volt off an inverter or certainly off a generator.

Some people use hand washing with either a 5 gallon bucket or a Wonder Washer. They work but I just have enough clothes to go a long time between rips to the laundromat. Even boondocking you have to go in to town often for water and food.
Bob

Does this process also refer to the Fantastic Vent/Fan? Just purchased and installed a 2250. Having a professional do the solar. The wires on the fan are so short, that I need to extend the length myself in order to save money and put the ceiling panels back up so they don’t have to charge me for the extra labor and so that I can complete the buildout and move on to trim work.

Will be starting my “on the road living” in 2 weeks and using your site as the best all inclusive source for information. Keep it up, there are lots of us newbies who reply on your experience.

Need to buy a 12V cooler and a lunch box stove and I’m nowhere near being an electrical wizard but have heard that rather than run these appliances off of the cig lighter outlet in my SUV, I should be using a stand alone battery so they can be used even when the SUV is turned off.

What type of battery and how do I attach 2 appliances with male cig lighter plugs?

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